gatehouse
/ˈɡeɪtˌhaʊs/Definitions
1. noun
A structure at the entrance of a castle, fortress, or other fortified building, typically containing a gate.
“The gatehouse of the medieval castle stood tall and proud.”
2. noun
A building at the entrance of a property, such as a large estate or a private residence.
“The gatehouse of the mansion was beautifully designed and maintained.”